A new copper (II) complex [Cu(dtne)] center dot (ClO4)(2) center dot CH3CH2OH, where dtne is 1,2-bis(1,4,7-triaza-1-cyclononyl)ethane, was prepared and characterized by X-ray crystallography. The result shows that in the complex the copper (II) adopts an octahedral coordination geometry. The cyclic voltammetry of the complex recorded in aqueous solution indicates a reversible one-electron redox reaction. The activity of dismutation of superoxide (center dot O-2(-)) of the complex in the riboflavin-methionine-nitro blue tetrazolium assay has been researched. (C) 2008 Elsevier B.V. All rights reserved.